Difference between revisions of "Nitrogen dioxide" - New World Encyclopedia
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− | '''Nitrogen dioxide''' is the [[chemical compound]] [[Nitrogen|N]][[Oxygen|O]]<sub>2</sub>. It is one of the several [[nitrogen oxide]]s. This reddish-brown [[gas]] has a characteristic sharp, biting odor. [[Nitrogen|N]][[Oxygen|O]]<sub>2</sub> is one of the most prominent air [[ | + | '''Nitrogen dioxide''' is the [[chemical compound]] [[Nitrogen|N]][[Oxygen|O]]<sub>2</sub>. It is one of the several [[nitrogen oxide]]s. This reddish-brown [[gas]] has a characteristic sharp, biting odor. [[Nitrogen|N]][[Oxygen|O]]<sub>2</sub> is one of the most prominent air pollutants and a poison by inhalation. |
+ | |||
+ | [[Image:N02-N2O4.jpg|none|thumb|300px|Nitrogen dioxide (NO<sub>2</sub>) gas converts to the colorless gas [[dinitrogen tetroxide]] (N<sub>2</sub>O<sub>4</sub>) at low temperatures, and converts back to NO<sub>2</sub> at higher temperatures. Both bottles in this photograph contain equal amounts of gas at different temperatures.]] | ||
+ | |||
+ | ==Preparation== | ||
+ | Nitrogen dioxide (NO<sub>2</sub>) is prepared by simple reaction of [[nitric acid]] (HNO<sub>3</sub>) over [[copper]] metal. The reaction is the following: | ||
+ | :4HNO<sub>3</sub>(aq) + Cu(s) → Cu(NO<sub>3</sub>)<sub>2</sub>(aq) + 2NO<sub>2</sub>(g) + 2H<sub>2</sub>O(L) | ||
==Safety and pollution considerations== | ==Safety and pollution considerations== | ||
Nitrogen dioxide is toxic by inhalation. Symptoms of poisoning ([[lung edema]]) tend to appear several hours after one has inhaled a low but potentially fatal dose. Also, low concentrations (4 ppm) will anesthetize the nose, thus creating a potential for overexposure. | Nitrogen dioxide is toxic by inhalation. Symptoms of poisoning ([[lung edema]]) tend to appear several hours after one has inhaled a low but potentially fatal dose. Also, low concentrations (4 ppm) will anesthetize the nose, thus creating a potential for overexposure. | ||
− | Long-term exposure to NO<sub>2</sub> at concentrations above 40–100 µg/m³ causes adverse health effects <ref> | + | Long-term exposure to NO<sub>2</sub> at concentrations above 40–100 µg/m³ causes adverse health effects<ref>{{cite web|url=http://www.euro.who.int/document/e79097.pdf|title=Health Aspects of Air Pollution with Particulate Matter,Ozone and Nitrogen Dioxide|accessdate=2008-02-25}}</ref>. |
+ | |||
+ | Nitrogen dioxide is formed in most [[combustion]] processes using [[air]] as the [[oxidant]]. At elevated temperatures [[nitrogen]] combines with [[oxygen]] to form nitrogen dioxide: | ||
+ | : 2O<sub>2</sub> + N<sub>2</sub> → 2 NO<sub>2</sub> | ||
+ | The most important sources of NO<sub>2</sub> are [[internal combustion engines]] <ref>{{cite journal|last=Son |first=Busoon |authorlink= |coauthors= Wonho Yang, Patrick Breysse, Taewoong Chung and Youngshin Lee|year=2004 |month=March|title=Estimation of occupational and nonoccupational nitrogen dioxide exposure for Korean taxi drivers using a microenvironmental model |journal=Environmental Research |volume=94 |issue=3 |pages=291-296 |id= |url= http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WDS-49WMV2W-1&_user=432163&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000020718&_version=1&_urlVersion=0&_userid=432163&md5=1568528cb723b88921f97d88ebddd336|accessdate= 2008-02-25 |quote=}}</ref>, [[thermal power station]]s and, to a lesser extent, [[pulp mill]]s.<ref>{{cite web|url=http://www.metsabotnia.com/en/default.asp?path=204,215,268,267 |title= Air emissions|publisher=Botnia|accessdate=2008-02-25}}</ref> | ||
+ | |||
+ | The map shown below, depicting results of satellite measurements over Europe, illustrates nitrogen dioxide as large scale pollutant, with rural background ground level concentrations in some areas around 30 µg/m³, not far below unhealthful levels. Nitrogen dioxide plays a role in atmospheric chemistry, including the formation of [[tropospheric ozone]]. | ||
+ | A recent study by researchers at the [[University of California, San Diego]], suggests a link between NO<sub>2</sub> levels and [[Sudden Infant Death Syndrome]]. <ref>{{cite web|url=http://www.medicineonline.com/news/12/1110/Sids-Linked-to-Nitrogen-Dioxide-Pollution.html|title=Sids Linked to Nitrogen Dioxide Pollution|accessdate=2008-02-25}}</ref> | ||
+ | [[Image:NO2 pollution europe hires.jpg|none|thumb|300px|NO<sub>2</sub> pollution levels in [[Europe]], from January 2003 to June 2004.]] | ||
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==See also== | ==See also== | ||
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* [[Nitryl]] | * [[Nitryl]] | ||
*[[Nitrous oxide]] or N<sub>2</sub>O, "laughing gas", a linear molecule, [[isoelectronic]] with [[carbon dioxide|CO<sub>2</sub>]] but with a nonsymmetric arrangement of atoms (NNO) | *[[Nitrous oxide]] or N<sub>2</sub>O, "laughing gas", a linear molecule, [[isoelectronic]] with [[carbon dioxide|CO<sub>2</sub>]] but with a nonsymmetric arrangement of atoms (NNO) | ||
− | *[[Nitric oxide]] or NO, a problematic pollutant | + | *[[Nitric oxide]] or NO, a problematic pollutant that is short lived because it converts to NO2 in the presence of free [[oxygen]]. |
*[[Nitrogen oxide|NO<sub>x</sub>]] = all of the above in unspecified proportions but tending toward NO<sub>2</sub>. | *[[Nitrogen oxide|NO<sub>x</sub>]] = all of the above in unspecified proportions but tending toward NO<sub>2</sub>. | ||
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* [[Birkeland-Eyde process]] | * [[Birkeland-Eyde process]] | ||
− | == References | + | ==References== |
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<references/> | <references/> | ||
==External links== | ==External links== | ||
− | + | *[http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc09/icsc0930.htm International Chemical Safety Card 0930] | |
− | *[http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc09/icsc0930.htm International Chemical Safety Card 0930] | + | *[http://www.npi.gov.au/database/substance-info/profiles/67.html National Pollutant Inventory - Oxides of nitrogen fact sheet] |
− | *[http://www.npi.gov.au/database/substance-info/profiles/67.html Oxides of nitrogen fact sheet] | + | *[http://www.cdc.gov/niosh/npg/npgd0454.html NIOSH Pocket Guide to Chemical Hazards] |
− | *[http://www.cdc.gov/niosh/npg/npgd0454.html NIOSH Pocket Guide to Chemical Hazards] | + | *WHO-Europe reports: [http://www.euro.who.int/document/e79097.pdf Health Aspects of Air Pollution (2003)] (PDF) and "[http://www.euro.who.int/document/E82790.pdf Answer to follow-up questions from CAFE (2004)] (PDF) |
− | *WHO-Europe reports: [http://www.euro.who.int/document/e79097.pdf Health Aspects of Air Pollution | + | *[http://www.greenfacts.org/air-pollution/nitrogen-dioxide-no2/index.htm Nitrogen Dioxide Air Pollution] |
− | *[http://www.greenfacts.org/air-pollution/nitrogen-dioxide-no2/index.htm Nitrogen Dioxide Air Pollution] | + | *[http://esamultimedia.esa.int/images/EarthObservation/pollution_global_hires.jpg Nitrogen dioxide pollution in the world (image)] |
− | *[http://esamultimedia.esa.int/images/EarthObservation/pollution_global_hires.jpg Nitrogen dioxide pollution in the world (image)] | + | *[http://www.compchemwiki.org/index.php?title=Nitrogen_dioxide Computational Chemistry Wiki] |
− | *[http://www.compchemwiki.org/index.php?title=Nitrogen_dioxide Computational Chemistry Wiki] | ||
− | [[Category: | + | [[Category:Nitrogen compounds]] |
− | [[Category: | + | [[Category:Oxides]] |
+ | [[Category:Bleaches]] | ||
+ | [[Category:Hazardous air pollutants]] | ||
+ | [[Category:Smog]] | ||
− | + | [[ar:ثانى أكسيد نيتروجين]] | |
+ | [[cs:Oxid dusičitý]] | ||
+ | [[de:Stickstoffdioxid]] | ||
+ | [[es:Dióxido de nitrógeno]] | ||
+ | [[fr:Dioxyde d'azote]] | ||
+ | [[it:Diossido di azoto]] | ||
+ | [[nl:Stikstofdioxide]] | ||
+ | [[ja:二酸化窒素]] | ||
+ | [[pl:Tlenek azotu(IV)]] | ||
+ | [[pt:Dióxido de azoto]] | ||
+ | [[ru:Оксид азота(IV)]] | ||
+ | [[sk:Oxid dusičitý]] | ||
+ | [[sl:Dušikov dioksid]] | ||
+ | [[fi:Typpidioksidi]] | ||
+ | [[sv:Kvävedioxid]] | ||
+ | [[zh:二氧化氮]] |
Revision as of 09:33, 25 May 2008
Nitrogen dioxide | |
---|---|
Identifiers | |
CAS number | [ | ]
Properties | |
Molecular formula | NO2 |
Molar mass | 46.0055 |
Appearance | brown gas |
Density | 1443 kg/m³, liquid 3.4 kg/m³, gas at 294.25 K |
Melting point |
-11.2°C (261.95 K) |
Boiling point |
21.1°C (293.25 K) |
Hazards | |
EU classification | Highly toxic (T+) |
NFPA 704 |
|
R-phrases | R26, R34 |
S-phrases | S1/2, S9, S26, S28,S36/37/39, S45 |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
Nitrogen dioxide is the chemical compound NO2. It is one of the several nitrogen oxides. This reddish-brown gas has a characteristic sharp, biting odor. NO2 is one of the most prominent air pollutants and a poison by inhalation.
Preparation
Nitrogen dioxide (NO2) is prepared by simple reaction of nitric acid (HNO3) over copper metal. The reaction is the following:
- 4HNO3(aq) + Cu(s) → Cu(NO3)2(aq) + 2NO2(g) + 2H2O(L)
Safety and pollution considerations
Nitrogen dioxide is toxic by inhalation. Symptoms of poisoning (lung edema) tend to appear several hours after one has inhaled a low but potentially fatal dose. Also, low concentrations (4 ppm) will anesthetize the nose, thus creating a potential for overexposure.
Long-term exposure to NO2 at concentrations above 40–100 µg/m³ causes adverse health effects[1].
Nitrogen dioxide is formed in most combustion processes using air as the oxidant. At elevated temperatures nitrogen combines with oxygen to form nitrogen dioxide:
- 2O2 + N2 → 2 NO2
The most important sources of NO2 are internal combustion engines [2], thermal power stations and, to a lesser extent, pulp mills.[3]
The map shown below, depicting results of satellite measurements over Europe, illustrates nitrogen dioxide as large scale pollutant, with rural background ground level concentrations in some areas around 30 µg/m³, not far below unhealthful levels. Nitrogen dioxide plays a role in atmospheric chemistry, including the formation of tropospheric ozone. A recent study by researchers at the University of California, San Diego, suggests a link between NO2 levels and Sudden Infant Death Syndrome. [4]
See also
- Nitryl
- Nitrous oxide or N2O, "laughing gas", a linear molecule, isoelectronic with CO2 but with a nonsymmetric arrangement of atoms (NNO)
- Nitric oxide or NO, a problematic pollutant that is short lived because it converts to NO2 in the presence of free oxygen.
- NOx = all of the above in unspecified proportions but tending toward NO2.
More esoteric nitrogen oxides include N2O5 and the blue species N2O3.
Oxidized (cationic) and reduced (anionic) derivatives of many of these oxides exist: nitrite (NO2−), nitrate (NO3−), nitronium or NO2+, and nitrosonium or NO+. NO2 is intermediate between nitrite and nitronium:
- NO2+ + e− → NO2
- NO2 + e− → NO2−
- Birkeland-Eyde process
ReferencesISBN links support NWE through referral fees
- ↑ Health Aspects of Air Pollution with Particulate Matter,Ozone and Nitrogen Dioxide. Retrieved 2008-02-25.
- ↑ Son, Busoon and Wonho Yang, Patrick Breysse, Taewoong Chung and Youngshin Lee (March 2004). Estimation of occupational and nonoccupational nitrogen dioxide exposure for Korean taxi drivers using a microenvironmental model. Environmental Research 94 (3): 291-296.
- ↑ Air emissions. Botnia. Retrieved 2008-02-25.
- ↑ Sids Linked to Nitrogen Dioxide Pollution. Retrieved 2008-02-25.
External links
- International Chemical Safety Card 0930
- National Pollutant Inventory - Oxides of nitrogen fact sheet
- NIOSH Pocket Guide to Chemical Hazards
- WHO-Europe reports: Health Aspects of Air Pollution (2003) (PDF) and "Answer to follow-up questions from CAFE (2004) (PDF)
- Nitrogen Dioxide Air Pollution
- Nitrogen dioxide pollution in the world (image)
- Computational Chemistry Wiki
ar:ثانى أكسيد نيتروجين cs:Oxid dusičitý de:Stickstoffdioxid es:Dióxido de nitrógeno fr:Dioxyde d'azote it:Diossido di azoto nl:Stikstofdioxide ja:二酸化窒素 pl:Tlenek azotu(IV) pt:Dióxido de azoto ru:Оксид азота(IV) sk:Oxid dusičitý sl:Dušikov dioksid fi:Typpidioksidi sv:Kvävedioxid zh:二氧化氮